The 9.4T magnetic resonance imaging laboratory is a joint facility between Stony Brook University (SBU) and Brookhaven National Laboratory (BNL) and has been operational since 2004. The growing user group mainly includes investigators from BNL, SBU and Cold Spring Harbor Laboratory. The current research projects involve 1H magnetic resonance spectroscopy (1HMRS) of rat and mouse brain, high resolution in vivo MR microscopy of the rodent brain, functional magnetic resonance imaging using echo-planar imaging (EPI) and cardiac and fluid flow dynamics. All of these applications (but especially 1HMRS and EPI) are dependent on careful gradient shim corrections to establish adequate field uniformity during acquisitions. Our current installed shim set is flawed due to weak shimming power and temperature instability resulting in local field inhomogeneity and significant frequency drift during acquisitions. We are therefore requesting funds for a new B-GA 12 Gradient Set with an internal Shim Set which is temperature stabilized with active water cooling. Clearly, the narrowed spectral line widths, and improved main field stability and overall field uniformity that this upgrade will provide will improve across the board the quality of all MR imaging acquisitions that are done in the facility and thus, benefit all users of our 9.4T MRI instrument. However, the greatest benefit of the requested shim set will be in the area of in vivo 1HMRS in the rat and mouse brain which include the majority of our users'research applications and focus. PUBLIC HEALTH RELEVANCE: The relevance of this research to public health is that the requested instrument will enable studies in transgenic mouse models of multiple sclerosis, Alzheimer's disease and depression and thus help enhance our understanding of processes leading to the diseases and ultimately to their treatment and prevention.